Sorry for the late reply and thanks for bringing this up. Sometimes it is easy to forget to add some basic functionality when you don’t need those on your own applications 
Unfortunately the package doesn’t provide any simple way to check if Tag is present and both checks that you have implemented are valid.
Maybe we could add these kind of helper functions to the package, so there is no need for everyone to figure these things out on their own. I created a new issue to GitHub: https://github.com/ttu/ruuvitag-sensor/issues/33. You can comment there or to this thread if you have some suggestions for other features.